Antenna calibration method and system

Abstract

Embodiments of this application disclose an antenna calibration method and system. The system includes a baseband processing unit, a remote radio unit, an antenna array, and a coupled antenna. The antenna array sends a radio frequency calibration signal sent by the baseband processing unit, or receive the radio frequency calibration signal. The remote radio unit provides a plurality of transmission channels, where the plurality of transmission channels correspond to a plurality of transmission ports. The coupled antenna receives the radio frequency calibration signal sent by the baseband processing unit, and transmit a coupled signal corresponding to the radio frequency calibration signal to the baseband processing unit, or send the radio frequency calibration signal. The baseband processing unit calibrates, based on a difference between the radio frequency calibration signal and the coupled signal, a plurality of to-be-sent baseband signals corresponding to the plurality of transmission channels.

1 . An antenna calibration system, wherein the antenna calibration system comprises a baseband processing unit, a remote radio unit, an antenna array, and a coupled antenna, wherein
 the baseband processing unit is connected to a first end of the remote radio unit, and the antenna array and the coupled antenna are respectively connected to a second end of the remote radio unit;   the antenna array is configured to:
 send, to a wireless network, a radio frequency calibration signal sent by the baseband processing unit, or 
 receive the radio frequency calibration signal, and transmit a coupled signal corresponding to the radio frequency calibration signal to the baseband processing unit, wherein the antenna array comprises a plurality of transmission ports; 
   the remote radio unit is configured to provide a plurality of transmission channels, wherein the plurality of transmission channels correspond to the plurality of transmission ports;   the coupled antenna is configured to:
 receive, in the wireless network, the radio frequency calibration signal sent by the baseband processing unit, and transmit the coupled signal corresponding to the radio frequency calibration signal to the baseband processing unit, or 
 send the radio frequency calibration signal to the wireless network; and 
   the baseband processing unit is configured to calibrate, based on a difference between the radio frequency calibration signal and the coupled signal, a plurality of to-be-sent baseband signals corresponding to the plurality of transmission channels.   
     
     
         2 . The antenna calibration system according to  claim 1 , wherein the plurality of transmission channels comprise a plurality of signal transmission channels and at least one calibration channel, wherein the plurality of transmission ports correspond to the plurality of signal transmission channels, and the coupled antenna corresponds to the at least one calibration channel. 
     
     
         3 . The antenna calibration system according to  claim 2 , wherein when the antenna calibration system is used for downlink signal calibration, the baseband processing unit is configured to send the radio frequency calibration signal through the plurality of signal transmission channels; and
 the coupled antenna is configured to couple the radio frequency calibration signal to the calibration channel, and transmit the coupled signal of the radio frequency calibration signal to the baseband processing unit through the calibration channel.   
     
     
         4 . The antenna calibration system according to  claim 2 , wherein when the antenna calibration system is used for uplink signal calibration, the baseband processing unit is configured to send the radio frequency calibration signal through the calibration channel; and
 the coupled antenna is configured to couple the radio frequency calibration signal to the signal transmission channel, and transmit the coupled signal of the radio frequency calibration signal to the baseband processing unit through the signal transmission channel.   
     
     
         5 . The antenna calibration system according to  claim 2 , wherein the antenna calibration system further comprises a digital phase shifter, and the coupled antenna is connected to a calibration channel by using the digital phase shifter. 
     
     
         6 . The antenna calibration system according to  claim 5 , wherein a quantity of coupled antennas is equal to a quantity of calibration channels; and
 when the antenna calibration system is used for downlink signal calibration, each coupled signal corresponding to each coupled antenna is transmitted to the baseband processing unit through one calibration channel.   
     
     
         7 . The antenna calibration system according to  claim 5 , wherein the antenna calibration system further comprises a combiner, a quantity of coupled antennas is greater than a quantity of calibration channels, and the antenna calibration system comprises one calibration channel; and
 when the antenna calibration system is used for downlink signal calibration, coupled signals corresponding to the coupled antennas are aggregated by the combiner into one channel of coupled signals, and transmitted to the baseband processing unit through the calibration channel.   
     
     
         8 . An antenna calibration method, wherein the method comprises:
 receiving a radio frequency calibration signal from a wireless network by using a coupled antenna, wherein the radio frequency calibration signal is sent by a baseband processing unit to the wireless network through transmission channels in a remote radio unit;   backhauling a coupled signal corresponding to the radio frequency calibration signal to the baseband processing unit through the transmission channels; and   calibrating a plurality of to-be-sent baseband signals in the baseband processing unit based on a difference between the coupled signal and the radio frequency calibration signal.   
     
     
         9 . The method according to  claim 8 , wherein the transmission channels comprise a plurality of signal transmission channels and at least one calibration channel, and the coupled antenna is connected to the at least one calibration channel. 
     
     
         10 . The method according to  claim 9 , wherein when the radio frequency calibration signal is sent by the baseband processing unit to the wireless network through the plurality of signal transmission channels, transmitting the coupled signal corresponding to the radio frequency calibration signal to the baseband processing unit through the transmission channels comprises:
 transmitting the coupled signal corresponding to the radio frequency calibration signal to the baseband processing unit through the at least one calibration channel.   
     
     
         11 . The method according to  claim 9 , wherein when the radio frequency calibration signal is sent by the baseband processing unit to the wireless network through the at least one calibration channel, transmitting the coupled signal corresponding to the radio frequency calibration signal to the baseband processing unit through the transmission channels comprises:
 transmitting the coupled signal corresponding to the radio frequency calibration signal to the baseband processing unit through the plurality of transmission channels.   
     
     
         12 . The method according to  claim 10 , wherein the method further comprises:
 adjusting, based on phase information of the radio frequency calibration signal, a phase of the coupled signal by using a digital phase shifter, wherein the digital phase shifter is located between the coupled antenna and the at least one calibration channel.   
     
     
         13 . The method according to  claim 8 , wherein the calibrating a plurality of to-be-sent baseband signals in the baseband processing unit comprises:
 calibrating phases and amplitudes of the plurality of to-be-sent baseband signals in the baseband processing unit.   
     
     
         14 . A base station comprising an antenna calibration system, wherein the antenna calibration system comprises a baseband processing unit, a remote radio unit, an antenna array, and a coupled antenna, wherein
 the baseband processing unit is connected to a first end of the remote radio unit, and the antenna array and the coupled antenna are respectively connected to a second end of the remote radio unit;   the antenna array is configured to:
 send, to a wireless network, a radio frequency calibration signal sent by the baseband processing unit, or 
 receive the radio frequency calibration signal, and transmit a coupled signal corresponding to the radio frequency calibration signal to the baseband processing unit, wherein the antenna array comprises a plurality of transmission ports; 
   the remote radio unit is configured to provide a plurality of transmission channels, wherein the plurality of transmission channels correspond to the plurality of transmission ports;   the coupled antenna is configured to:
 receive, in the wireless network, the radio frequency calibration signal sent by the baseband processing unit, and transmit the coupled signal corresponding to the radio frequency calibration signal to the baseband processing unit, or 
 send the radio frequency calibration signal to the wireless network; and 
   the baseband processing unit is configured to calibrate, based on a difference between the radio frequency calibration signal and the coupled signal, a plurality of to-be-sent baseband signals corresponding to the plurality of transmission channels.   
     
     
         15 . The base station according to  claim 14 , wherein the plurality of transmission channels comprise a plurality of signal transmission channels and at least one calibration channel, wherein the plurality of transmission ports correspond to the plurality of signal transmission channels, and the coupled antenna corresponds to the at least one calibration channel. 
     
     
         16 . The base station according to  claim 15 , wherein when the antenna calibration system is used for downlink signal calibration, the baseband processing unit is configured to send the radio frequency calibration signal through the plurality of signal transmission channels; and
 the coupled antenna is configured to couple the radio frequency calibration signal to the calibration channel, and transmit the coupled signal of the radio frequency calibration signal to the baseband processing unit through the calibration channel.   
     
     
         17 . The base station according to  claim 15 , wherein the antenna calibration system further comprises a digital phase shifter, and the coupled antenna is connected to a calibration channel by using the digital phase shifter. 
     
     
         18 . The base station according to  claim 17 , wherein a quantity of coupled antennas is equal to a quantity of calibration channels; and
 when the antenna calibration system is used for downlink signal calibration, each coupled signal corresponding to each coupled antenna is transmitted to the baseband processing unit through one calibration channel.   
     
     
         19 . The base station according to  claim 17 , wherein the antenna calibration system further comprises a combiner, a quantity of coupled antennas is greater than a quantity of calibration channels, and the antenna calibration system comprises one calibration channel; and
 when the antenna calibration system is used for downlink signal calibration, coupled signals corresponding to the coupled antennas are aggregated by the combiner into one channel of coupled signals, and transmitted to the baseband processing unit through the calibration channel.